How can I get rid of all this noise
500 samples is really a small number for most scenes. Turn that up to 1500 or 2000 and see how it looks then. There are ways to make more samples render faster, but the only way to really get rid of noise is more samples.

The issue of noise in Cycles has already been covered well in other answers, so I won't duplicate that here. Search the site, and you will find all the information we have to offer.

This answer is the best place to start: How to avoid noisy renders in Cycles?